There are a lot of definitions out there, but essentially it's the intersection between research evidence, clinical expertise, and patient preferences. Some more examples:

• Evidence-based nursing is an approach to health care practice that enables nurses to provide the highest quality care based on the best evidence available to meet he needs of their patients. - Melnyk & Fineout-Overholt, 2005
• The integration of the best research evidence with clinical expertise and patient values. - Sackett et al., 2000
• Synthesizing scientific evidence to improve quality and effectiveness in health care.  AHQR, 2012

• Provides up-to-date care
• Helps us digest the volume of nursing and medical research in the literature
• Encourages patients and nurses to work together to make informed decisions
• Reduces cost for patients and hospitals
• Fosters professional responsibility

UVA Health EBQI Microsystem-Level Model

-Revised from The Iowa Model-

At UVA Health, we use a model that combines the tenets of a literature review (with evidence assessment and grading) with the structure of a quality improvement project. 

EBP asks if our current policies, standard work, and procedures reflect the best evidence available. The goal is to find the best known way to produce a specific outcome in a specific population. We do a literature review, appraise what we find, consider the results in relation to our population, and make recommendations.

QI asks if we are optimally performing the current standard, policy, practice set by our organization when delivering care. We might search the literature to find interventions that when implemented improve our methods/systems -- we test these interventions to see if they improve our performance in meeting our organization's standards.

Our model is EBPQI -- we still ask a question geared toward finding the best evidence, look at the research evidence, grade the evidence we find, and then we use that to pilot an evidence-based intervention/change. Afterwards, we assess to see if it impacted our care (our desired outcome) and if the change can (and should) be implemented long-term.